Device for interchangeable lenses for switching between exposure meter operation and manual exposure operation

ABSTRACT

A device for interchangeable lenses of screw mount type for switching between EE (electronic eye) exposure operation and manual exposure operation is provided which generally comprises an EE aperture setting ring, an EE-Manual switching ring which is also used as a manual aperture setting ring, and a rocking lever which may be selectively engaged with either of said two rings. When the switching ring is set to the manual exposure operation, the rocking lever engages with the manual aperture setting cam surface of the switching ring and is limited in rotation, but when the switching ring is set to the EE exposure operation, the rocking lever is disengaged from the manual aperture setting cam surface and is engaged with the EE aperture setting cam surface of the EE aperture setting ring and is limited in rotation. An aperture blade actuating ring is rotated in response to the angle of rotation of said rocking lever to close aperture blades to a selected aperture.

United States Patent Hokari [75] Inventor: Saburo Hokari, Kawasaki-shi,Japan [73] Assignee: Ricoh Co., Ltd., Tokyo, Japan [22] Filed: May 10,1972 [21] Appl. No.: 251,977 [30] I Edi-cit; Appiicaan Pridrit; 15a;

May 10, 1971 man. f. 1 .1 Ill [52] US. Cl 95/64 R, 95/64 B [51] Int. Cl.G03b 9/02 [58] Field of Search 95/42, 64 R, 64 B [56] References CitedUNITED STATES PATENTS 3,352,220 11/1967 Lang et al. 95/64 R 3,442,1925/1969 Sato 95/64 B UX 3,466,994 9/1969 l-lolderbaum.. 95/64 B 3,470,80610/1969 Uno 95/42 3,590,714 7/1971 Schops 95/64 B UX [4 1 Oct. 16, 1973Primary Examiner-Samuel S. Matthews Assistant ExaniinerE. M. BeroAttorney-Henry T. Burke et a1.

[57] ABSTRACT said two rings. When the switching ring is set to themanual exposure operation, the rocking lever engages with the manualaperture setting cam surface of the switching ring and is limited inrotation, but when the switching ring is set to the BE exposureoperation, the rocking lever is disengaged from the manual aperturesetting cam surface and is engaged with the EB aperture setting camsurface of the EB aperture setting ring and is limited in rotation. Anaperture blade actuating ring is rotated in response to the angle ofrotation of said rocking lever to close aperture blades to a selectedaperture.

5 Claims, 4 Drawing Figures DEVICE FOR INTERCHANGEABLE LENSES FORSWITCHING BETWEEN EXPOSURE METER OPERATION AND MANUAL EXPOSURE OPERATIONBACKGROUND OF THE INVENTION The present invention relates to adevice'forinterchangeable lenses of screw mount type for use with single-lensreflex cameras of EB type for switching between EE (electric eye)exposure operation and manual exposure operation.

The same inventor has disclosed an EE exposure control mechanism for BBsingle-lens reflex cameras of'the type using interchangeable lenses ofscrew mount type in which a coupling ring on the side of a camera bodyand an EE aperture setting ring onthe side of an interchangeable lenswhich are normally not operatively coupled to each other may becorrectly operatively coupled when a shutter button or the like isreleased so that the positive and secure coupling therebetween may beestablished even though the relative angular position between the lensmount on the side of the camera body and the interchangeable lenschangesfrom-time to time when mounted. When the EB exposure operation isswitched'to the manual exposure operation a coupling member which hasbeeninterconnecting between an EE aperture setting ring and an aperturering is disconnected from the latter, and whenthe manual exposureoperationisswitchedto the BE exposure operation, a manual aperturesetting ring is disconnected from the aperture ring. From the standpointof the camera operation, it is most desirable that'a ring for switchingbetween EE exposure operationandmanual operation to be referred to asEE-Manual switching ring be used also as a manual aperture setting ring.

In the EB single-lens cameras of the type mounting bayonet mount typeinterchangeable lenses, the angular displacement of the EE-Manualswitching ring may be transmitted with ease to the camera body, butinthe BE single-lens cameras of the type mounting interchangeable lensesof screw mount type, the systems used in the interchangeable lenses ofbayonet mount type cannot be used because the relative angular positionbetween the interchangeable lens of screw mount type and the camera bodyor lens mount changes from time to time.

SUMMARY OF THE INVENTION Briefly stated, according to the presentinvention, an interchangeable lens of screw mount type is provided withan EE aperture setting ring and an EE-Manual switching ring. A rockinglever which controls an aperture ring is so biased as to normally engagewith one of the two rings, but in response to the angular displacementof the EE-Manual switching ring, the rocking lever is caused todisengage from the one ring so as to engage with the other ring; Hence,the switchingbetween the BE exposure operation and manual exposureoperation of the side of the interchangeable lens may be effectedindependently of the mechanism on the side of the camera body.

As described above, according to the present invention the switchingbetween EE exposure operation and manual exposure operation may beeffected independently of the mechanism on the side of the camera body,the device of the present invention is'best suited for use with theinterchangeable lenses of screw mount 2 type whose relative angularposition when mounted on the camera body changes from time to time andfrom one to another.

Furthermore, the interchangeable lenses of screw mount typeincorporating the present invention may be of course mounted on thecameras of lens mount type other than the EB cameras. The aperturesetting cams are provided separately for the EB and manual exposureoperations so that the spacing between the adjacent graduated aperturescales may' be increase and the gradient of the curve of thedisplacement-time diagram for a cam for controlling the rocking levermay be made small. As a result, the error in position of the EB andmanual aperture setting rings will less adversely affect the accuracy ofa selectedaperture, and the graduatedaperture scales may be more clearlyviewed. Moreover, it is no required to stop the rotation of the EBaperture setting ring so that the number of parts used for switchingbetween EE and manual exposure operations may be reduced, and theaccuracy will not be adversely affected at all by the switching betweenthe BE and manual exposure operations.

The above and other objects, features and advantages of the presentinvention will become more apparent from the following description ofthe preferred embodiments thereof taken in conjunction with theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1A is a perspective exploded viewillustrating major component parts of a device for switching between EEand manual exposure operations for inter changeable lenses of screwmount type in accordance with the present invention, said deviceconstituting one specific embodiment of the invention;

FIG. 1B is a perspective view illustrating on enlarged scale anencircled portion A in FIG. 1A;

FIG. 2 is a perspective exploded view illustrating an EE exposurecontrol mechanism on the side of a camera body which is used inconjunction with the device of the present invention; and

FIG. 3 is a fragmentary sectional view of a second embodiment of theinvention incorporating a variation of a rocking lever switchingmechanism in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As used in the followingdescription, the term EE exposure operation will be understood to referto operation wherein the diaphragm aperture of a camera is set by anexposure meter which includes an electric eye. The term manual exposureoperation refers to operation wherein the diaphragm aperture is setmanually. The term EE aperture setting ring refers to a ring(incorporated in the device of the invention) which cooperates withother elements in effecting the setting of the diaphragm aperture by theexposure meter. The term EE-manual switching ring refers to a ring (alsoincorporated in the device of the invention) which serves the dualfunctions of switching between exposure meter setting and manual settingof the diaphragm aperture and providing the means for manually settingthe aperture.

Referring first to FIGS. 1A and 18, there is shown a first embodiment ofthe invention, adapted for use with a single-lens reflex camera havingan exposure meter (including an electric eye) for setting the diaphragmaperture, and a screw mount for threadedly mounting a lens barrelcontaining a suitable camera lens. Herein, the lens will be referred toas an interchangeable lens because it and its associated barrel can beremoved from the screw mount and replaced with another lens and barrel,and the term optical axis will be understood to refer to the opticalaxis of the interchangeable lens. In this embodiment, an EE-Manualswitching ring which is rotated for setting the camera into the BEexposure operation or the manual exposure operation has a manualaperture setting cam surface In formed at one portion of the innerperiphery and a switching projection 1b extending from the back of thering 1 toward the film in parallel with the optical axis of theinterchangeable lens. The EE exposure index mark and the manual aperturesetting marks are graduated around the outer periphery of the EE-Manualswitching ring 1. An EE aperture setting ring 2 has an EE aperturesetting cam surface 2a formed at one portion of the inner periphery andan EE coupling pin 2b extending from the back of the ring toward thefilm (not shown) within the camera body. The angular position of the EBaperture setting ring 2 is controlled through the coupling pin 2b by anEE exposure control mechanism incorporated in the camera. An aperturering 3 which is rotatably mounted on a lens barrel has a pin 3aextending forwardly in parallel with the optical axis and a plurality ofcam grooves 3b which are directed radially and are disposed inequiangular spaced apart relation with each other. A spring 4 is loadedbetween the pin 3a and the stationary member (not shown) of theinterchangeable lens in order to bias the aperture ring 3 to normallyrotate in the clockwise direction. A stationary aperture ring 5 has aplurality of equiangularly spaced apart holes 5a into which are looselyfitted pins 6a of aperture blades 6 (only one being shown in FIG. 1A).Pins 6b of the aperture blades 6 are loosely fitted into the elongatedslots 3b of the aperture ring 3.

A semicircular sector lever which is pivoted with a pivot pin 8 has apin 7a extending from the free end thereof and engaging with the pin 3aextending from the aperture ring 3. An actuating lever 9 which ispivoted with the pivot pin 8 coaxially of the sector lever 7 has a bentportion 9a in engagement with the sector lever 7 for preventing therelative rotation between the actuating lever 9 and the sector lever 7.A cone-shaped free end of an aperture setting pin 11 which is displacedin parallel with thev optical axis is in engagement with the side edgeof the actuating lever 9. A rocking lever 12 is pivoted to one end of aleaf spring 13 with a pivot 13a, and has a pair of coaxial pins 12a and12b extending forwardly and backwardly in parallel with the opticalaxis. The free end 120 of the rocking lever 12 isin engagement withthepin 3a of the aperture ring 3. The base 13b of-the leaf spring 13 issecurely fixed to the lens barrel. Underthe condition shown in FIG. 1,the pin 12a is biased toward the EE-Manual switching ring 1 under theforce of the leaf spring 13. When the EE-Manual switching ring isrotated from the position shown in FIG. 1 in the clockwise direction tothe EB exposure position, the switching projection 1b forces the pivot13a to move in parallel with the optical axis so that the pin 12a isreleased from the cam surface la whereas the pin 12b is caused to engagewith the cam surface 2a of the EB aperture setting ring 2. In otherwords, the rocking lever 12 moves angularly (on pivot 13a) about an axiswhich extends parallel to the aforementioned optical axis of theinterchangeable lens. The rocking lever is also translatable (togetherwith its pivot 13a) along its axis of angular movement, i.e., in eitherof two opposed directions along a path parallel to the optical axis, formovement of the pins 12a and 12b as described; this translation of therocking lever is produced by the described movement of pivot 13a (towhich it is attached), in either of two opposed directions parallel tothe optical axis, by spring 13 and projection 1b.

Next referring to FIG. 2, the BE exposure control mechanism incorporatedin the camera body and dis closed by the inventor will be brieflydescribed hereinafter because the device of the present invention isused together with this control mechanism. The control mechanism has acoupling ring 101 which is rotatably mounted around the lens mount (notshown) of the camera body and has a groove 101a. An error compensatingpawl 102 which is pivoted to the coupling ring 101 with a pivot 103 isbiased under the force of a spring 104 loaded between the coupling ring101 and the error compensating pawl 102 so that the latter is normallyrotated in the counterclockwise direction. The error compensating pawl102 has a saw-toothed portion 102a whose length must be longer than thetolerance in the direction of the circumference of the lens mountallowed when the interchangeable lens is mounted on the camera. Aconnecting lever 105 is pivoted to a pin 106 extending from the couplingring 101, and an EE cam lever 107 is pivoted to the camera body with apivot 108 and is caused to rotate in the clockwise direction when theconnecting lever 105 is lowered. One arm of the EB cam lever 107 ispivoted to the connecting lever 105 whereas the other arm is providedwith a cam surface 107a. A pointer catcher 110 which is pivoted to thecamera body with a pivot 111 and is biased to normally rotate in theclockwise direction under the force of a spring 112, is adapted to catchtogether with the EEcam lever 107 a pointer 113a of an exposure meter113 so that the angle of rotation of the coupling ring 101 may becontrolled in response to the angle of deflection of the pointer 113a ofthe exposure meter 113. A slide lever 114 is vertically displaced by amechanism (not shown) so as to raise or lower a'mirror frame (notshown). A rocking lever 115 which is pivoted to the camera body with apivot 116 is biased to normally rotate in the counterclockwise directionunder the force of a spring 117, and has a coupling pin 115a and a bentportion 11511. A connecting lever 118 which is pivoted to the rockinglever 115 with a pivot 115s is biased to normally rotate in theclockwise direction under the force of a spring 119, and the rotation ofthe connecting lever 118 is limited by the bent portion 11512 of therocking lver 115. A bell crank 120 which is pivoted to the camera bodywith a pivot 121 has apin 120a extending from the free end of one armthereof and loosely fitted between a pair of arms of a bifurcated end118a of the connecting lever 118. A pin 12% at the other end of the bellcrank 120 is loosely fitted into the groove 101a of the coupling ring101. A release lever 122 which is pivoted to the camera body with apivot 123 is biased to normally rotate in the counterclockwise directionunder the force of a spring 126 and has a horizontally bent portion orprojection 112a in engagement with the lower end of a release button124. A clutch lever 126 which is pivoted to the camera body with a pivot127 has its free end engaged with the undersurface of the free end ofthe pointer catcher 110, a pin 126a in engagement with the undersurfaceof the release lever 122, and a pin 126k in engagement with theundersurface of the free end of the error compensating lever 102. Theclutch lever 126 is biased to normally rotate in the counterclockwisedirection under the force of the spring 109, whose spring force must begreater than the sum of the forces of the springs 104 and 112.

Therefore in the normal position the release lever 122 is biased torotate in the counterclockwise direction under the force of the spring125; the clutch lever 126 is also biased to rotate in thecounterclockwise direction under the force of the spring 109; thesawtoothed portion 102a of the error compensating pawl 102 is releasedfrom the coupling pin 2b extending from the interchangeable lens and thepointer catcher 110 is rotated in the counterclockwise direction so thatthe pointer 113a of the exposure meter 113 is released.

Next the mode of operation will be described. When the release button124 is depressed, the release lever 122 is caused to rotate in theclockwise direction so that the pin 126a causes the clutch lever 126 torotate in the clockwise direction against the spring 109. As a reuslt,the error compensating pawl 102 and the pointer catcher 110 are releasedand the pointer catcher 110 is caused to rotate in the clockwisedirection under the force of the spring 112 to press the pointer 113aagainst a stationary member. The error compensating pawl 102 is causedto rotate in the counterclockwise direction underthe force of the spring104 so that one of the saw teeth 102a engages with the coupling pin 2bextending from the interchangeable lens. Thereafter the slide lever 114is raised under the force of a spring (not shown) so that the couplingring 101 is caused to rotate in the clockwise direction through therocking lever 115, the connecting lever 118, and the bell crank 120.Then, the EB cam lever 107 is caused to rotate in the clockwisedirection through the pin 106 and the connecting lever 105 to engagewith the pointer 113a. Therefore, the rotations of the coupling ring101, the bell crank 120 and the connecting lever 118 are now stopped,and thereafter only the rocking lever 115 is permitted to further rotatethrough a predetermined angle by the slide lever 114 while charging thespring 119. Since the coupling pin 2b of the EB aperture setting ring 2on the side of the interchangeable lens is in engagement with one of thesaw teeth 102a of the error compensating pawl 102, it is rotated inunison with the coupling ring 101 so that the EB aperture setting ring 2is rotated through an angle in response to the angle of deflection ofthe pointer 113a of the exposure meter 113. In this case, the mirrorframe (not shown) is raised by a mechanism (not shown) so that theaperture pin 11 extends. As a result, the cone-shaped free end 11a ofthe aperture pin 11 causes the actuating lever 9 to rotate in thecounterclockwise direction so that the sector lever 7 is caused torotate in the counterclockwise direction under the force of the spring10. The pin 7a of the sector lever 7 forces the pin 3a of the aperturering 3 against the spring 4 so that the aperture ring 3 is caused torotate in the counterclockwise direction and the aperture blades 6 areclosed to a selected aperture. Next the shutter mechanism is actuatedand upon completion of the shutter operation the slide lever 114 islowered to return the mirror frame (not shown) to its normal position sothat the aperture pin 11 is returned to the normal position to open theaperture blades and that the component parts in the mechanism forcoupling the interchangeable lens to the Eli exposure control mechanismin the camera body are all returned to their initial positions.

As will be apparent from the foregoing description and from the showingof FIG. 1A, the aperture-setting pin 11 extends in a direction parallelto the optical axis of the interchangeable lens, and is operativelyinterconnected with the aforementioned mirror frame so as to movelongitudinally (i.e., in a direction parallel to the optical axis) incorrespondence with raising and lowering of the mirror frame. When themirror frame is raised (after depression of release button 124, butbefore operation of the shutter), pin 11 is thereby moved longitudinallyoutwardly (i.e., away from the film in the camera), bringing the widerportion of its cone-shaped end 11a into engagement with lever 9 andthereby depressing lever 9 so as to release lever 7 for apertureclosingupward (counterclockwise) movement. When the mirror frame is loweredupon actuation of the shutter, pin 11 is retracted longitudinallyinwardly (toward the film) so that the narrower portion of its conicalend 11a engages lever 9, permitting upward (clockwise) motion of lever 9for restoration of lever 7 and the diaphragm elements to their initialpositions. In other words, in the described device the counterclockwisemovement of lever 7 by spring 10 provides the force for closing theaperture, such closure being limited (through the agency of rockinglever 12) either by the exposure meter or a manual setting (now to bedescribed) so as to achieve the desired aperture setting; and theoutward longitudinal movement of pin 11 upon raising of the mirror frameacts on lever 9 to permit such counterclockwise movement of lever 7 eachtime the mirror frame is raised. In case of the manual exposureoperation in which the EE-Manual switching ring 1 is located in theposition shown in FIG. 1, the switching projection 1b is out ofengagement with the pivot 1.3a so that the pin 12a of the rocking lever12 is pressed against the manual aperture setting cam surface 1a underthe force of the leaf spring 13, but the pin 12b is out of engagementwith the BE aperture setting cam surface 2a. The rotation of the rockinglever 12 which in turn controls the rotation of the sector lever 7 underthe force of the spring 10 is limited because the pin 12a engages withthe manual aperture setting cam surface 1a of the EE- Manual switchingring 1. Therefore, the aperture may be set independently of the rotationof the BE aperture setting ring 2.

In case of the BE exposure operation, the EE-Manual switching ring 1 isrotated to the EB position. Then the projection 1b of the ring 1 pushesthe pivot 13a toward the camera body against the leaf spring 13 so thatthe pin 12b may now engage with the EB aperture setting cam surface 2awhereas the pin 12a is out of engagement with the manual aperturesetting cam surface 1a. Therefore, the angle of rotation of the rockinglever 12 is now controlled in response to the angle of rotation of theBE aperture setting ring 2 so that the aperture is set in response tothe angle of deflection of the pointer 113a in the manner describedhereinbefore.

In the instant embodiment described above, the leaf spring 13 is used toengage or release the pins 12a and 12b of the rocking lever 12 with orfrom the manual and EE aperture setting cam surfaces In and 2a, but thepresent invention provides a variation as shown in FIG. 3. That is, FIG.3 illustrates in pertinent detail a second embodiment of the inventiondiffering from the abovedescribed embodiment in that, in place of leafspring 13, there is provided a coiled spring 13b for serving the samefunction of biasing the rocking lever 12 (in its path of translationalmotion parallel to the optical axis) toward ring 1. In this secondembodiment, a bush 12d over which is fitted the rocking lever 12 isfitted over a pin 13a securely fixed to the lens barrel, and a coiledspring 13b is loaded between the bush 12d and a stationary member (notshown) so that in case of the manual aperture setting operation the pin12a may be pressed against the manual aperture setting cam surface 1 aunder the force of the coiled spring 13b. In case of the BE aperturesetting operation, the projection 1b presses the bush 12d against thecoiled spring 13b so that the pin 12b may be pressed against the BEaperture setting cam surface 2a for BB exposure operation.

What is claimed is:

1. For an interchangeable camera lens of screw mount type, for use witha camera having means including a rotatable coupling ring for effectingsetting of a diaphragm aperture by an exposure meter, a device forswitching between exposure meter aperture-setting operation and manualaperture-setting operation, said device comprising:

a. a first ring mounted for rotation, about an optical axis of aninterchangeable lens, in coupled relation to and in unison with saidcoupling ring, said first ring having a first cam surface;

b. a second ring manually rotatable about said optical axis and spacedfrom said first ring along said axis, said second ring having a secondcam surface;

c a third rotatable ring for controlling the opening of a diaphragmaperture in correspondence with the angular position of said third ring;

d. an angularly movable rocking lever for controlling the angularposition of said third ring in accordance with the angular position ofsaid rocking lever, said rocking lever being alternately engageable withsaid first and second cam surfaces for control of the angular positionof the rocking lever by the cam surface engaged thereby, and saidrocking lever being translatable along a path parallel to said opticalaxis into selective engagement with either of said first and second camsurfaces;

I e. means for exerting a biasing force on said rocking lever in a firstdirection along said path to urge said rocking lever into position forengagement with one of said cam surfaces; and

. means for translating said rocking lever along said path against saidbiasing force to move said rocking lever out of position for engagementwith said one cam surface and into position for engagement with theother of said cam surfaces.

2. A device as defined in claim 1, including lens barrel structuresupporting said lens, and wherein said biasing means comprises a leafspring having opposite ends respectively fixed to said structure andsupporting said rocking lever.

3. A device as defined in claim 1, including lens barrel structuresupporting said lens, and wherein said biasing means comprises a coilspring interposed between said structure and said rocking lever.

4. In a device for selectively effecting setting of a camera diaphragmaperture by an exposure meter and manually, the combination including a.first and second rings rotatably mounted in spaced relation along acommon axis, each of said rings having a cam surface, the first ringbeing couplable to means for rotating said one ring through an angledetermined by an exposure meter, and the second ring being rotatablemanually;

b. a third ring rotatable to control the opening of a diaphragmaperture;

c. an angularly displaceable rocking lever for limiting the extent ofrotation of said third ring in accordance with the angular position ofsaid rocking'lever, disposed intermediate said two rings for translationalong a path parallel to said common axis into selective engagement witheither of said cam surfaces for limitation of the angular position ofthe rocking lever by the cam surface with which it is engaged;

d. means for biasing said rocking lever along said path into engagementwith said cam surface of said second ring; and

e. means carried by said second ring and positionable by manual rotationthereof for pushing said rocking lever along said path, against theforce of said biasing means, out of engagement with the cam surface ofsaid second ring and into engagement with the cam surface of said firstring.

5. In a camera having a camera body with a screw mount and structureincluding a lens removably mounted thereon, aperture-controllingapparatus including a. an adjustable aperture-defining diaphragmremovable with the lens;

b. a rotatable coupling ring carried by the camera body; and

c. an exposure meter carried by the camera body for controlling theextent of rotation of the coupling ring;

wherein the improvement comprises:

d. a first ring, removable with the lens and mounted for rotation aboutan optical axis of the lens in coupled relation to and in unison withsaid coupling ring, said first ring having a first cam surface;

e. a second ring removable with the lens, manually rotatable about theoptical axis, and spaced from the first ring along the axis, said secondring having a second cam surface;

f. a third rotatable ring, removable with the lens, for

controlling the aperture of said diaphragm in correspondence with theangular position of said third ring;

g. an angularly movable rocking lever, removable with the lens, forcontrolling the angular position of said third ring in accordance withthe angular position of said rocking lever, said rocking lever beingalternately engageable with said first and second cam surfaces forcontrol of the angular position of the rocking lever by the cam surfaceengaged thereby, and said rocking lever being translatable along a pathparallel to said optical axis into selective engagement with either ofsaid first and second cam surfaces, for setting of said aperture by saidexposure meter when said rocking lever is in eni. means, removable withsaid lens, for translating said rocking lever along said path againstsaid biasing force to move said rocking lever out of position forengagement with said one cam surface and into position for engagementwith the other of said cam surfaces.

1. For an Interchangeable camera lens of screw mount type, for use witha camera having means including a rotatable coupling ring for effectingsetting of a diaphragm aperture by an exposure meter, a device forswitching between exposure meter aperturesetting operation and manualaperture-setting operation, said device comprising: a. a first ringmounted for rotation, about an optical axis of an interchangeable lens,in coupled relation to and in unison with said coupling ring, said firstring having a first cam surface; b. a second ring manually rotatableabout said optical axis and spaced from said first ring along said axis,said second ring having a second cam surface; c a third rotatable ringfor controlling the opening of a diaphragm aperture in correspondencewith the angular position of said third ring; d. an angularly movablerocking lever for controlling the angular position of said third ring inaccordance with the angular position of said rocking lever, said rockinglever being alternately engageable with said first and second camsurfaces for control of the angular position of the rocking lever by thecam surface engaged thereby, and said rocking lever being translatablealong a path parallel to said optical axis into selective engagementwith either of said first and second cam surfaces; e. means for exertinga biasing force on said rocking lever in a first direction along saidpath to urge said rocking lever into position for engagement with one ofsaid cam surfaces; and f. means for translating said rocking lever alongsaid path against said biasing force to move said rocking lever out ofposition for engagement with said one cam surface and into position forengagement with the other of said cam surfaces.
 2. A device as definedin claim 1, including lens barrel structure supporting said lens, andwherein said biasing means comprises a leaf spring having opposite endsrespectively fixed to said structure and supporting said rocking lever.3. A device as defined in claim 1, including lens barrel structuresupporting said lens, and wherein said biasing means comprises a coilspring interposed between said structure and said rocking lever.
 4. In adevice for selectively effecting setting of a camera diaphragm apertureby an exposure meter and manually, the combination including a. firstand second rings rotatably mounted in spaced relation along a commonaxis, each of said rings having a cam surface, the first ring beingcouplable to means for rotating said one ring through an angledetermined by an exposure meter, and the second ring being rotatablemanually; b. a third ring rotatable to control the opening of adiaphragm aperture; c. an angularly displaceable rocking lever forlimiting the extent of rotation of said third ring in accordance withthe angular position of said rocking lever, disposed intermediate saidtwo rings for translation along a path parallel to said common axis intoselective engagement with either of said cam surfaces for limitation ofthe angular position of the rocking lever by the cam surface with whichit is engaged; d. means for biasing said rocking lever along said pathinto engagement with said cam surface of said second ring; and e. meanscarried by said second ring and positionable by manual rotation thereoffor pushing said rocking lever along said path, against the force ofsaid biasing means, out of engagement with the cam surface of saidsecond ring and into engagement with the cam surface of said first ring.5. In a camera having a camera body with a screw mount and structureincluding a lens removably mounted thereon, aperture-controllingapparatus including a. an adjustable aperture-defining diaphragmremovable with the lens; b. a rotatable coupling ring carried by thecamera body; and c. an exposure meter carried by the camera body forcontrolling the extent of rotation of the coupling ring; wherein theimprovement comprises: d. a first rinG, removable with the lens andmounted for rotation about an optical axis of the lens in coupledrelation to and in unison with said coupling ring, said first ringhaving a first cam surface; e. a second ring removable with the lens,manually rotatable about the optical axis, and spaced from the firstring along the axis, said second ring having a second cam surface; f. athird rotatable ring, removable with the lens, for controlling theaperture of said diaphragm in correspondence with the angular positionof said third ring; g. an angularly movable rocking lever, removablewith the lens, for controlling the angular position of said third ringin accordance with the angular position of said rocking lever, saidrocking lever being alternately engageable with said first and secondcam surfaces for control of the angular position of the rocking lever bythe cam surface engaged thereby, and said rocking lever beingtranslatable along a path parallel to said optical axis into selectiveengagement with either of said first and second cam surfaces, forsetting of said aperture by said exposure meter when said rocking leveris in engagement with said first cam surface and for manual setting ofsaid aperture when said rocking lever is in engagement with said secondcam surface; h. means, removable with the lens, for exerting a biasingforce on said rocking lever, in a first direction along said path tourge said rocking lever into position for engagement with one of saidcam surfaces; and i. means, removable with said lens, for translatingsaid rocking lever along said path against said biasing force to movesaid rocking lever out of position for engagement with said one camsurface and into position for engagement with the other of said camsurfaces.